Outdoor clothing can be divided into the main underwear, warmth and coat three. Underwear: The main purpose of outdoor underwear is to keep the body skin dry. If the sweat from the body causes the surface evaporation will take away the body's enormous heat, so that people feel cold. Therefore, underwear should be synthetic fiber material underwear, avoid wearing pure cotton, pure wool underwear. The role of warm clothing is to form the air layer inside the garment. Air is a good heat insulation medium, in the warmth of the formation of the air layer, outside the cold air and the body separated, to maintain the purpose of body temperature. Coat: The coat of mountaineering, outdoor sports generally refers to the emergency clothing, rush pants, raincoat and other clothing, its main function is waterproof, windproof, tear-proof. With the development of science and technology, the rush underwear has developed GORE-TEX, FIRST-TEX and other waterproof breathable fabrics. The principle is that in the film state, the surface of the pore diameter is precisely between the water molecules and steam molecules, the vapor molecules can pass, and water molecules are blocked, thus to achieve the effect of waterproof breathable.